This invention relates to a digital transmission and control system for vehicles, and more specifically such a system which replaces the traditional analog system employing cable harnesses in vehicles such as automobiles, agricultural equipment, and the like.
The traditional analog system employing wire harnesses is an essential design feature in transportation and construction vehicles, agricultural and manufacturing equipment, and other devices where:
(1) electro-mechanical, electric, and/or electronic devices1 are connected to instrument panels that allow human or computer operators to monitor and control their operation through the generation and transmission of electrical or electronic signals and/or
(2) electro-mechanical, electric, and/or electronic devices2 are connected together into systems in which the devices communicate with and control one another and react to changes in the external environment through the generation and transmission of electrical or electronic signals.
1 The electro-mechanical, electric, and/or electronic devices referenced in this patent application include: (1) transducers, (2) indicating devices, such as lights and meters, (3) control devices, such as switches, buttons, and levers, (4) electric motors, (5) electrically and/or electronically controlled mechanical devices such as hydraulic systems, and (5) all other such devices as are currently incorporated within systems that utilize wire-harnesses. 
Currently these systems employ wire harnesses, typically comprising hundreds of individual conductors, each dedicated to controlling and/or communicating with one of many different devices. Thus, for example, in an automobile, one set of wires in a harness might indicate whether certain lights are operating, another set of wires might indicate the level of illumination the lights are providing (high beam/low beam), and additional sets of wires might provide power for power controllers that turn the lights on or off and/or control the level of the lights. Even in automobiles, the large number of devices that must be monitored and controlled results in complex and bulky wire harnesses comprising dozens of individual wires. In aircraft and other more complex systems, wire harnesses frequently comprise thousands of individual wires.
These complex wire harnesses create many design, engineering, and construction problems. Their geometry and weight must be taken into account when designing the total system of which they are a part. For example, in aircraft design, certain structural members may have to be modified or moved to allow for the installation of bulky wire harnesses comprising hundreds of individual wires. Furthermore, because these harnesses are so large, the harness design must frequently be modified to take account of limitations imposed by the total structure. Wire harnesses must frequently have complex topologies, e.g., splits and branches involving bundles of hundreds of individual wires, because the harnesses must fit within pre-designated places and individual wires in the harness must connect to the appropriate devices.
After the wire harnesses for a particular system have been designed they must be constructed. This involves the design and construction of complex templates and/or armatures. After these templates and/or armatures are built, either workers must be instructed in how to load wires into them and splice appropriate bundles of wire together, or complex machinery must be programmed for the same task. The sheer number of wires involved leaves large latitude for errors to occur. Therefore each harness must be frequently tested, to determine that wires are appropriately bundled and directed within the harness.
During construction, large wire harnesses may weigh enough that they require considerable effort to move. They may also require effort to install into the systems of which they become apart. In extreme instances this may involve ad hoc modifications during the construction process, e.g., the widening of a hole in a structural member. The prior art teaches a plethora of inventions to deal with the problem of wire harness and installation. Typical among these is the patent by Gold, U.S. Pat. No. 5,371,942.
Wire harnesses are also subject to problems during use. Friction between insulated wires in the same harness may abrade insulation. This can lead to the failure of wire harness components. In extreme cases, such problems have resulted in short circuits, electrical fires, and even total system failure.
It may be necessary, on occasion, to alter wire harnesses during the operational lifetime of the systems within which they are incorporated. For example, such alterations might be required for reasons of safety, economy, or improved technology. Changing the configuration of wire harnesses after they have been incorporated into an operating system, e.g., a ship, aircraft, or automobile, is expensive and difficult.
To summarize, the current technology for wire harnesses results in bulky bundles of wires that often have complex topologies. These harnesses create design and engineering constraints. They must be manufactured and incorporated into the systems of which they are a part by using complex and expensive procedures that may be prone to error. Wire harnesses are also subject to wear during use that can result in system failure. It is difficult to change the configuration or operating characteristics of a wire harness after it has been incorporated into the system of which it forms a part.
The wire harness is well adapted to the basically analog system which communicates between transducers, switch closures, and voltage levels as input devices, and analog meters, indicators, and annunciators as outputs. This analog system has been the only economically feasible system available since the development of the vehicles in which they are used. However, the current state of the digital technology now makes it possible to replace the analog system with a digital one.
They key to the use of a digital system is the central computer bus, which replaces the wire harness. The bus make be one of many different types: arrays multi-conductor lines, optical bundles, waveguides are all applicable for this purpose. Furthermore, serial transmission may be used in the main bus, so that a single coaxial cable, or dual twisted pair cables, may form the central spine of this system.
The electrical system may be thought of as the analog of a computer network, in which the remote inputs and outputs form network nodes. The nodes require several devices for their operation: first, there must be a local bus which communicates between the main bus and the node. Next there must be a digital controller, with addressing capability to isolate data intended for the node, and, in the case of serial data transmission, to convert it to parallel data for further processing. A converter is also usually necessary to convert the digital data to analog, and vice versa. And finally, there must be data processing capability, either at the node itself, or via a central microprocessor which collects data from all the inputs, processes the data, and produces outputs accordingly.
Because of continuing miniaturization and increase in computing power of modern microprocessor technology, the cost of the elements required at the node is now sufficiently low to make such a system economically feasible. Installation costs will be reduced, as traditional cables are expensive to fabricate, install, and test. Modularization of the elements will further reduce construction costs. The digital system lends itself to self-testing, reducing maintenance. And the resulting system will have a reduced weight and complexity.
Advantages of the Digital System
This invention will, in many cases, be able to replace an extremely heavy, bulky, and topologically complex analog system with its attendant wire harness comprising hundreds of individual wires with one bi-directional or unidirectional signal bus, an optional power bus and individual tap lines attached to these bus lines by appropriate connectors.
The bi-directional or uni-directional signal bus and tap lines will be composed either of a single wire, cable, optical cable, wave guide, or another type of bi-directional or uni-directional, signal carrying device. Bus and tap lines will terminate in processors that are specially designed and programmed to generate, prioritize, receive, and process either token packets, switched wave packets, or other types of signals used in computer networks. Such microprocessors may be designed and built for each such bus and tap line system or created by programming off-the-shelf hardware.
Depending upon geometry, it may sometimes be necessary to provide local bus line branches, or taps, from the main signal bus. These local bus lines require the use of break-outs, or fan-outs, which allow these branches to the nodes terminating these branches, without degrading the transmission quality of the main bus. Examples of these break-outs for optical signal buses are described in the patents by Caron, U.S. Pat. No. 5,394,502, and Pilatos, U.S. Pat. No. 5,659,655.
Electro-mechanical, electrical, and electronic devices will attach, either directly or through appropriate converters, to the terminating microprocessors. When such a device is operated or otherwise generates information, the microprocessor to which the device is attached will generate a signal identifying the device and prioritizing and coding the information that is generated. The microprocessor will then pass this information to the signal bus and signal tap lines as a token packet, switched wave packet or other type of signal. All microprocessors will receive this signal, decode it, determine its priority and, when appropriate, process the signal and pass it to the appropriate, attached converters, electro-mechanical devices, electrical devices, and/or electronic devices, in an appropriate form. In cases where an appropriate response to a signal will be to apply or turn off power to given devices, signals can be sent to the appropriate power controllers attached to the optional power bus line. Many devices will thus be able communicate with and control one another via one signal bus line and an optional power bus line rather than by a complex and bulky set of wire harnesses and attachments.
This invention will greatly simplify the design, engineering and construction of systems that currently require large, complex wire harnesses. The use of one bus line and associated tap lines will generate great reductions in weight and bulk. Less concern will be needed in designing systems that currently incorporate the placement of complex wire harnesses, since it will be relatively much easier to plan the placement of a single bus line and associated tap lines and microprocessors. The effort currently given to designing the topology of complex wire harnesses, designing templates and/or armatures for their construction, and training workers or programming machines in harness construction procedures will be eliminated.
Although additional effort may be required to program and/or design microprocessors for use as terminators in the single bus system described in this patent application, the effort involved will usually be less than is currently needed to design and construct complex wire harnesses. Construction costs for the single bus system will also be minimal and construction will be less onerous and error prone than is the case with complex wire harnesses.
Redundancy can be an important safety consideration in aircraft and other applications. This invention will also allow for greater redundancy. Many-wired, wire harnesses are bulky, and duplicating them within a given space may be difficult or impossible. The single signal bus and optional power bus composing a large physical part of this invention take(s) up little space. It would, therefore, be relatively easy to incorporate duplicates of these buses into any given system; thus increasing redundancy and safety.
Operational safety will be further enhanced because this invention will reduce the possibility, inherent in many-wired wire harnesses, of friction between wires leading to insulation failure. Such insulation failures can cause wire harness systems to malfunction and, in extreme cases, generate electrical fires. Because this invention will greatly reduce the number of wires required in any system it will reduce the possibility of system failures due to friction between wires.
A further advantage of this invention is that it will allow simplification of control panels by allowing many control panel instruments and readouts to be simplified and/or perform more functions than would be the case with wire harnesses. This is because much of the functionality of control panel instrumentation can be incorporated within the microprocessors and microprocessor programs that are part of the invention.
A simple example will make this clear. Currently on many cars a multi-setting switch controls windshield wiper speed. This switch directly controls the speed of the motor driving the windshield wipers. Such switches are expensive and many wires connect them to the windshield wiper motor.
With the current invention a much simpler, less expensive, and easier to use system could replace the multi-setting switch. A simple push button would send a pulse signal through the signal bus to the appropriate microprocessor. This microprocessor would store the current state of the windshield wiper motorxe2x80x94off, lowest speed, higher speed, highest speedxe2x80x94and, through the appropriate connecting device, ratchet up the speed of the motor every lime the control panel button is pushed. When the button is pushed while the motor is running at its highest speed the microprocessor could be programmed to send a signal that shuts the motor off.
Incorporating wire harness functionality within the microprocessors and microprocessor programs that are part of the invention will also, in many instances, facilitate inexpensive changes to existing systems that are already incorporated in aircraft, automobiles, and other applications. With the current invention such changes may frequently be accomplished by re-programming or replacing the system""s microprocessors. Changes to wire harness systems, in contrast, may require extensive rewiring that is usually expensive, time-consuming, and error-prone. Similarly, design changes will be much easier to facilitate with the current invention than is the case with wire harness systems.
Finally, incorporating the functionality of wire harness systems within the microprocessors and microprocessor programs that are part of the invention will allow embodiments of this invention that would either be impossible with standard wire harness systems or would require very complex systems. For example, the microprocessors and their programs can retain a history of activities in the system and determine the processing of future signals based upon this history. Thus, a heat detection and alarm system might be triggered not just when an indicator detects a certain level of heat, but when the first or second derivative of heat increase exceeds a boundary value.
It is an object of the current invention to provide a digital electronic system to replace the analog system currently used in automobiles and other vehicles. It is a further object of this invention to implement the analog system using a digital signal bus to replace the multi-conductor cable harness used in the prior art.
According to one aspect of the current invention, a transmission and control system for vehicles communicates with a multiplicity of input and output devices. The invention includes a bi-direction digital data bus and a multiplicity of nodes, each connected to the data bus. Each node further includes a converter connected to the input or output device at the node, and a digital processor, electrically connected to the converter and to the bus, communicating data from the bus to the converter.
According to a second aspect of the invention, one or more of the nodes control power devices a power bus, electrically connected to each power control nodes, is also included.
According to a third aspect of the invention, a power tap is included at each power control node, each such power tap connected at one end to the power bus, and connected at the other end to a controller.
According to a fourth aspect of the invention, a central microprocessor electrically connected to the signal bus is included.
According to a fifth aspect of the invention, the controllers are intelligent controllers.
According to a sixth aspect of the invention, a multiplicity of signal break-outs, a signal break out are included, a break-out located at each node, connected at one end to the signal bus, and at the other end to the local bus.
According to a final aspect of the invention, the converters further include one or more members of the group which consists of digital to analog converters, analog to digital converters, relays, transponders, solenoids, and solid state switches.